.wmv will not upload without Invalid file

i have a few large wmv files i need to get on here. But every time I get an Invalid file message. ive used different browsers, and ive used both the basic and pro up loaders but still i get the same message. ive checked the formatting according to your compression requirements and everything seems to be in order. it finishes the upload just fine but when i click go to video i get an invalid file message. what is the problem?